Special Paper 356: Two anomalies of platinum group elements above the Cretaceous-Tertiary boundary at Beloc, Haiti: Geochemical context and consequences for the impact scenario

TitleSpecial Paper 356: Two anomalies of platinum group elements above the Cretaceous-Tertiary boundary at Beloc, Haiti: Geochemical context and consequences for the impact scenario
Publication TypeBook
Year of Publication2002
AuthorsStüben, D, Kramar, U, BERNER, ZSOLT, Eckhardt, J-D, Stinnesbeck, W, Keller, G, Adatte, T, Heide, K
Volume356
Number of Pages163 - 188
PublisherGeological Society of America
Abstract

A detailed geochemical investigation of an expanded Cretaceous-Tertiary (K-T) boundary section near Beloc (B3), Haiti, reveals a complex pattern of sedimentation of multiple origins as a result of erosional, biogenic, volcanic, and impact events. Carbonate-rich uppermost Maastrichtian sediments with high excess rates for Cu, Zn, and Sr (biogenic origin) indicate high productivity (δ13C) and warm temperatures (δ18O). These sediments are overlain by Paleocene (early Danian zone P1a) spherulerich clayey layers that indicate lower productivity, lower temperatures, and high input of glass and biogenic carbonate. Reworked Maastrichtian sediments are mixed with spherule-rich layers. This spherule-rich deposit is topped by a thin layer rich in Fe that also contains an Ir-dominated anomaly of platinum group elements (PGE) with an almost chondritic abundance pattern, which appears to be the result of a cosmic influx. Monotonous limestones above this interval reflect recovery to normal pelagic sedimentation, which is interrupted by a second PGE anomaly in an Fe-rich clayey layer in the middle part of zone P1a. All PGEs are enriched in this interval and the PGE pattern is basalt like, suggesting a volcanic source. Both PGE anomaly horizons coincide with productivity and temperature changes.  PDF

URLhttp://www.gsajournals.org/perlserv/?request=get-specialpub-toc&isbn=0-8137-2356-6http://specialpapers.gsapubs.org/cgi/doi/10.1130/0-8137-2356-6.163
DOI10.1130/0-8137-2356-610.1130/0-8137-2356-6.163